Activation of mTOR coincides with autophagy during ligation-induced atrophy in the rat submandibular gland

Salivary gland atrophy is a common consequence of pathology, including Sjögren's syndrome, irradiation therapy and obstructive sialadenitis. During severe atrophy of the rat submandibular gland caused by excretory duct ligation, the majority of acinar cells disappear through apoptosis, whereas ductal cells proliferate and dedifferentiate; yet, the gland can survive in the atrophic state almost indefinitely, with an ability to fully recover if deligated. The control mechanisms governing these observations are not well understood. We report that ∼10% of acinar cells survive in ligation-induced atrophy. Microarray and quantitative real-time PCR analysis of ligated glands indicated sustained transcription of acinar cell-specific genes, whereas ductal-specific genes were reduced to background levels. After 3 days of ligation, activation of the mammalian target of rapamycin (mTOR) pathway and autophagy occurred as shown by phosphorylation of 4E-BP1 and expression of autophagy-related proteins. These results suggest that activation of mTOR and the autophagosomal pathway are important mechanisms that may help to preserve acinar cells during atrophy of salivary glands after injury

The assessment of oral dryness by photographic appearance of the tongue

Background Oral dryness or hyposalivation is a major clinical problem. Several chairside tests or visual inspections of the oral cavity have been proposed for the assessment. Objective To identify whether photographs of the tongue could be used to identify oral dryness. Material and methods Twenty-five dentists and 25 individuals with another academic background were recruited. They assessed the severity of the oral dryness of 50 patients, based on an intraoral picture of each patient. The oral dryness was quantified with a five-point Likert scale and the scores were subsequently compared with the salivary flow rate and the level of xerostomia of these patients. Results No relation was found between the unstimulated salivary flow rate of a patient and the average oral dryness score, determined by dentists (p = 0.260) as well as non-dentists (p = 0.806). Also no relation was found between the self-reported xerostomia level of the patient and the average dryness score assessed by the dentists (p = 0.171) or non-dentists (p = 0.477). Conclusion It does not seem possible to diagnose oral dryness by mere visual inspection of photographed tongues. Thus, for correct diagnosis of oral dryness further clinical investigation of the oral cavity and collection of saliva is indicated